The invention relates to a recuperator burner for heating a volume such as a furnace space, or also the interior space of a jet pipe.
Recuperator burners are used e.g. for the direct or indirect heating of industrial furnaces. In direct heating, the oxidation of the fuel takes place in the furnace space. In indirect heating, for example by means of a jet pipe, the combustion takes place within a pipe (jet pipe) that extends into the furnace space but is closed relative to said furnace space, thus causing said pipe to be heated and to emit thermal radiation.
An example of a recuperator burner, with or without jet pipe, is disclosed by document EP 0 685 683 B1. Herein, the recuperator is located in the furnace wall and has a typical length of 400 mm and, depending on burner output, a diameter of 100-300 mm. This recuperator consists of ribbed segments of high-temperature cast steel or also of ceramic material. In order to reduce the generation of nitrogen oxide, a strong exhaust gas recirculation is established in the heated volume, thus leading to a so-called “flameless oxidation.” This operation is also referred to as FLOX® operation (FLOX is a registered trademark of WS-Warmeprozesstechnik GmbH). Burners of this design have an efficiency of 65 to 75%.
The same publication also discloses a regenerator burner. This regenerator burner comprises two heat-storing regenerators that are alternately heated by exhaust gas, or they release their thermal energy to the supplied combustion air. Such regenerator burners achieve an efficiency of up to 90%. However, due to the control arrangement required for the alternating operation of the two regenerators to achieve the constant flow reversals, such an arrangement causes increased expenses and efforts for installation and control.
It is therefore the object of the present invention to provide a recuperator burner with simplified operability and improved operating efficiency.